US5235609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor laser device
Assignee: Rohm Co Ltd
•
Filing: 1991-10-18
•
Granted: 1993-08-10
•
Expires: 2011-10-18
Abstract
Abstract A semiconductor laser device comprises: an active layer; a lower clad layer provided below the active layer; an upper clad layer provided above the active layer; and a current blocking layer, provided above the upper clad layer, for limiting an active region of the active layer in a direction along a width to make the active region of a striped form which has a wide portion and a narrow portion. According to the device, coherence of an oscillated laser beam is reduced, thereby to decrease a feedback induced noise when used for a pickup of an optical information recording/reproducing apparatus.
Inventors
- 👤 Satoshi Uchida
- 👤 Kaoru Kusunoki
- 👤 Masato Mushiage
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:01
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/1053; H01S5/1064; H01S5/20; H01S5/22; H01S5/223; H01S5/2231
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
A semiconductor laser device comprising: an active layer having a cavity; a lower clad layer provided below said active layer; an upper clad layer provided above said active layer; a current blocking layer, provided above said upper clad layer, for limiting an active region of said active layer in a direction along a width of said active region to make said active region of a stripe form, said stripe-form active region having a narrow portion which is narrower than a predetermined width of said stripe-form active region, wherein said active layer, said lower clad layer, said upper clad layer and said current blocking layer form an accumulated layer; and a pair of electrodes provided at an upper and a lower end of said accumulated layer; wherein oscillation occurs in a plurality of modes of different standing wave configurations in order to simultaneously generate laser beams of the plurality of modes.
Claim 2
Dependent Claim
150 words
A semiconductor laser device comprising: an active layer having a cavity; a lower clad layer provided below said active layer; an upper clad layer provided above said active layer; a current blocking layer, provided above said upper clad layer, for limiting an active region of said active layer in a direction along a width of said active region to make said active region of a stripe form, said stripe-form active region having a narrow portion which is narrower than a predetermined width of said stripe-form active region, wherein said active layer, said lower clad layer, said upper clad layer and said current blocking layer form an accumulated layer; and a pair of electrodes provided at an upper and a lower end of said accumulated layer; wherein oscillation occurs in a plurality of modes of different standing wave configurations in order to simultaneously generate laser beams of the plurality of modes.
Claim 3
Dependent Claim
32 words
A semiconductor laser device according to claim 1, wherein said active layer consists of AlGaAs, said lower clad layer consists of N-type AlGaAs, and said upper clad layer consists of P-type AlGaAs.
Claim 4
Dependent Claim
38 words
A semiconductor laser device according to claim 1, wherein a protecting layer having a band gap equal to or larger than that of said active layer is provided between said upper clad layer and said current blocking layer.
Claim 5
Dependent Claim
28 words
A semiconductor laser device according to claim 1, wherein said narrow portion includes a portion having a constant width and a portion having a width which continuously varies.
Claim 6
Dependent Claim
29 words
A semiconductor laser device according to claim 1, wherein multi-mode oscillation occurs so that beam intensity discontinuously and gradually decreases when wavelength increases or decreases from a predetermined wavelength.
Claim 7
Dependent Claim
91 words
A semiconductor laser device having an active region of a stripe form, comprising: an active layer having a cavity; a lower clad layer provided below said active layer; an upper clad layer provided above said active layer; a pair of electrodes provided at an upper and a lower end of an accumulated layer comprising said active layer, said lower clad layer and said upper clad layer, wherein a plurality of narrow portions are provided at portions other than both ends, in a direction along the length of said stripe-form active region.
Claim 8
Dependent Claim
91 words
A semiconductor laser device having an active region of a stripe form, comprising: an active layer having a cavity; a lower clad layer provided below said active layer; an upper clad layer provided above said active layer; a pair of electrodes provided at an upper and a lower end of an accumulated layer comprising said active layer, said lower clad layer and said upper clad layer, wherein a plurality of narrow portions are provided at portions other than both ends, in a direction along the length of said stripe-form active region.
Claim 9
Dependent Claim
32 words
A semiconductor laser device according to claim 6, wherein said active layer consists of AlGaAs, said lower clad layer consists of N-type AlGaAs, and said upper clad layer consists of P-type AlGaAs.
Claim 10
Dependent Claim
38 words
A semiconductor laser device according to claim 6, wherein a protecting layer having a band gap equal to or larger than that of said active layer is provided between said upper clad layer and said current blocking layer.
Claim 11
Dependent Claim
28 words
A semiconductor laser device according to claim 6, wherein said narrow portion includes a portion having a constant width and a portion having a width which continuously varies.
Claim 12
Dependent Claim
29 words
A semiconductor laser device according to claim 6, wherein multi-mode oscillation occurs so that beam intensity discontinuously and gradually decreases when wavelength increases or decreases from a predetermined wavelength.
References Cited (Backward Citations)
US4359776A
Cited
US4594718A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-09 | 1997-02-08 | 1997-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-09 | 2001-02-08 | 2001-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-09 | 2005-02-08 | 2005-08-10 | $7700.00 | Window Closed / Lapsed |